Over the recent years, developments of information technologies have involved scaling up a system configuration and advancing multifunction such as increasing a CPU (Central Processing Unit) count, a memory capacity or an I/O (Input/Output) device count in an information processing apparatus. The advancements of the scale-up and the multifunction, however, lead to a tendency of increasing initial diagnosis steps in the startup of the information processing apparatus and elongating a period of time from the time when the startup is started to the time when the device reaches a usable status, i.e., a startup time.
Therefore a variety of techniques for reducing the startup time of the information processing apparatus are proposed.
Provided are, e.g., a startup mode in which device detection for detecting the devices such as CPUs (Central Processing Unit), memories and I/O (Input/Output) devices is performed and a startup mode in which the device detection is omitted using past detected results stored in a nonvolatile memory, in which the mode is selected based on a period of time of pressing a power source switch. With this mode selection, if the device detection is unnecessary, the startup time is reduced by omitting the detection.
Further, such an apparatus is proposed that stores connection status of devices in the nonvolatile memory at the startup immediately after configuration change, and reduces the startup time by making the use of contents in the nonvolatile memory at the subsequent startup.    Patent document 1: Japanese Laid-Open Patent Publication No. 2006-259903    Patent document 2: Japanese Laid-Open Patent Publication No. 2003-84981
In the case of reducing the startup time by selecting the omission of the device detection, such a problem exists that inconvenience arises if there is a discrepancy between the past detected result and the device configuration.
Further, in the case of storing the connection status of the devices when the configuration is changed, the devices must be again detected at the startup after changing the configuration, therefore this is not a fundamental solution.